Write the function of each of the following:
1. amacrine cell
2. anterior chamber
3. bipolar cell
4. choroid
5. ciliary body
6. ciliary fibers
7. cone
8. conjunctiva
9. cornea
10. fovea
11. ganglion cell
12. horizontal cell
13. iris
14. lens
15. light rays
16. optic nerve
17. posterior chamber
18. retina
19. rod
20. sclera
21. vitreous body